Insulator



Feb. 14, 1928.

A. O. AUSTIN INSULATOR Filed 0013.20, 1921 awwmtoz Guam El-2E OHIO BRASS COMPANY, OF lvIAhl'SI-IELD, OHIO A JERSEY.

COREC'RATZON OF NEW I1 SULATOR.

Application filed. October 20, 19521.

This invention relates to insulators especially adapted for high tension use and has for its ol'ject the improvement of surface gradient reduction or elimination of surand the provision of insulators which shall be of im proved construction and operation generally.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawing and described in the following specification.

In the drawing the figure is an elevation partly in section of an insulator embodying one form of the present invention.

In the embodiment shown in the drawing a dielectric member is provided with a holding member or cap .11, secured to the dielectric member in any suitable manner as by cement 12. An opening is provided within the dielectric member 10 for receiving a pin 13, secured in place by cement 1s. The dielectric member 10 is provided with a flange petticoat 15, such as commonly provided in insulators of the class shown in the drawing. The insulator may be used as one of a series string. or may be employed for supporting a conductor, or for any other purpose for which insulators are employed. The supported load is represented in broken lines at 16 in the drawing.

Ad'accnt the lower ed 'e of the can 11 and i b .L 7

extending outwardly therefrom is a thin metal disc or flange 17. This flange as shown in the drawing is, in electrical con nection with the cap 11, and projects out-' wardly therefrom in the general direction of the surface of the dielectric flange 15. but is spaced from the surface of the dielectric flange. The outer edge of the flange 17 is turned backwardly to provide a rounded portion 18 at the outermost part of the flange. This prevents the edge of the flange 17 from projecting in a. direction which might give rise to streamers or discharging arcs, and provides a smooth curved surface from which the static lines of force emanate. A similar conductor flange 19 connected with the pin 13 and extends in the general direction of the lower surface of the flange 15. The-flange 19 is also bent backwardly to provide a rounded surface 20 to prevent concentration of stress and dis charge at the edge. As shown in the drawing, the flanges 1'? and 19 are of materially less diameter than the flange 15 to prevent concentrate in streamers which tend to Serial No. 568,935.

i'..terference with the eificiencv of the insul tor and to keep the metallic flanges out of the 11116 of drip from the dielectric flana'e of the same or other insulator in a seriesf Tn insulators having projecting flanges or etticoats the charging and leakage currents over the surface of the insulators will encounter a resistance on the surface of the flange which v ries greatly for the portions of the flange at different distances from the center thereof. The surface area adjacent the center of the flange is relatively small. but increases with the distance from the center. For this reason the resistance to charging and leaka e currents is lar 'elv concentrated in a narrow Zone adjacent tlie inner portion of the flange. This may give r se to streamers or arcs near the inner portion of the flange which are detrimental to the dielectric material and which cause shunting of the surface insulation and are otherwise objectionable.

lVith the conductor flanges 17 and 19 omitted as in previous constructions, the leakage and the greater part of the charging current will flow outwardly along the surface. At high voltage the currentma flow out over the surface. These streamers mav be regarded as conducting paths whose re sistance drops off very rapidly with an increase inthe current flowi g iii same. This current is usually made up of a combining and surface leakage current. If e current in are streamers is reduced or eliminated, their resistance will be increased and their detrimental in loweri g the insulation of the surface will be minimized.

By providing the conductor flanges 17 and 19, part of the cha ing current may be supplied through the air. This will cut down the charging current which tends to start from the cap and pin and therebv tend to maintain the effective insulation or flashover voltage of the surface.

The between the distance conductor flanges 17 and 19 and the insulating surfac of the flange 15 will vary in accordance with the result desired. The ii'ivention i1n proves the surface gradient and voltage which may be carried safely by the insulating member, particularly where conditions are unusually severe. Being separated from the insulated surface. they do not reduce or cut out the surface or reduce the surface ill) resistance of the insulator for leakage in any way. Either one or both conductorflanges may be used, it generally being advisable to use the flange adjacent to the surface tending tohave the highest concentration of stress.

Conductor flanges which are properly formed and separated from the surface will not decrease the flash-over ofagiven diame ter of insulating member as is the usual case where. plates are placed in contact to-reg-ulatethe relativegradient of a series of insulators: The conducting flanges may be made an integral part of the main attachments 11- and13' or where the insulating elements are used. in: a series the conducting member 19 may be connected; toaconnect-ing menu-- berl? which may-be immediately belowit. Another object of. the members isto pro-'- vide a smooth surface and lower the concentration of stress so as to increase the flash-over voltage between" adgacent sides: of

the 'insulating member. This is particularly true of the conducting flange 1-9 which. will I protect. discharge from rivets or cot-ters or other shar-ppointson the attachments. V

In theinvention it is desirablegto so regulate the clearance that the charging current tending to radiate: from the mainrattach mentswillzbe reduced toa minimum but'the clearance between the conducting: flanges and the surface must notbe'soreduced' that arcs will form bet-ween ,the'members and the surface-f the dielectric.

. In general, there is nochange in the elec trostatic distributionin a'series of insulators by the addition of the conductorflanges owing tov theirelectrostatic capacity to ground.

I: claim:

1. An insulator. comprising a dielectric member having. a; radially extending flange thereon, terminal members connected with said insulator at opposite sides ofi said flange, and means connected with each of. said terminal members for supplyingchargjing current to said flange at pointsspacedi member having a radially extending flange thereon, terminal members connected with said insulatorsat opposite sides of said flange, and means for supply ng: charging current to said flange, comprising apair of sheet metal plates connected one with each of said terminal members and extending radially therefrom 1n gradually increasing spaced relation relative to Silld dlelectrlc flange, said plates being curved to form I rounded surfaces at the edges thereof and being of materially; less diameter than the dielectric flange. I

3. An insulator comprising a dielectric member having: a: radially extending flange thereon, said flange bemgcurved downwardly-toprov1dea hollow opemng Mill'jS-lOWGI side, terminal members connected with said insulator at. opposite sides of said flange,

and means' for supplying: charging current to said flange, said means comprising a pair of: sheet metal platesconnected one with each of said terminal members and extending'r'adially therefrom 1n gradually 1ncreas= ing'ispacecb relation relative to said dielectric flange, each plate being; less than threefourths the diameter of said flange and the lower plate having? its: inner edge disposed within the hollowformed by the downward curvature of said flangeto bring'i said inner edgeclosely'adjacent' the'lower. face of said flange.

In testnnony whereof I have signed my.

na'meto thisspeciflcation onthis 12th day of; @otober, A; D: 1921. V i

ARTHUR o; AUSTIN. 

